Device for locking and unlocking by means of a wrench, a plug or lid on a frame, notably of a manhole

ABSTRACT

A device for locking and unlocking a wrench, a plug or lid on a frame, notably of a manhole. A bolt is mounted and guided in translation in a casing of the plug and is held in a locking position by a pre-stressed coil compression spring, between the bolt and a bottom wall of the casing, the bolt ( 8 ) comprising a transverse branch on which an end of the wrench may act in order to displace the bolt towards a position for unlocking the plug from the frame.

FIELD OF THE INVENTION

The present invention relates to a device for locking and unlocking bymeans of a wrench, a plug or lid on a frame, notably of a manhole.

BACKGROUND

Such a device comprising a lock integral with the plug is known, whichhas an aperture opening out providing access to the lock for the wrenchincluding an arm with an end with which the lock may be maneuvered whenthe wrench is introduced into the aperture of the plug from a lockingposition in which a bolt of the lock is retained captive by a keeper ofthe frame to an unlocking position for which the bolt is released fromthe keeper.

However, this known device is of a relatively complex structure takinginto account the numerous components involved and is relatively costly.

The object of the present invention is to propose a device for lockingand unlocking by means of a wrench, a plug or lid on a frame, which inparticular is suitable for ensuring children's safety and which has asimple and economical structure.

For this purpose, according to the invention, the device for locking andunlocking by means of a wrench, a plug or lid on a frame, comprising alock integral with the plug which has an aperture opening out providingaccess to the lock for the wrench including an arm with an end withwhich the lock may be maneuvered when the wrench is introduced into theaperture of the plug from a locking position in which a bolt of the lockis retained captive by a keeper of the frame to an unlocking positionfor which the bolt is released from the keeper, is characterized in thatthe bolt is removably mounted and guided in translation in a casing ofthe plug, is held in its locking position by a coil compression springinterposed between the bolt and a bottom wall of the casing, and has itsend adjacent to the spring including a branch transverse to thelongitudinal direction of the bolt extending through two guiding groovesrespectively formed in two side walls of the casing parallel to thelongitudinal direction of the bolt, at least one of the guiding groovespassing through the corresponding side wall of the casing and into whichthe end of the arm of the wrench may be introduced, which may act on thecorresponding end of the bolt's transverse branch in order totranslationally displace the latter towards its position of release fromthe keeper against the return force of the spring.

The side wall of the casing including the through-groove furthercomprises a slot perpendicular to this wall, opening out into thethrough-groove and allowing the maneuvering end of the arm of the wrenchto be introduced into the groove.

The wrench comprises a handle parallel to the arm with a maneuvering endand a bar connecting the handle to the arm, the handle, the bar and thearm with a maneuvering end of the wrench being located in a same planeand the aperture of the plug providing access to the lock being a slotextending in a plane perpendicular to the longitudinal direction of thebolt and allowing the arm and its maneuvering end to be introduced bydisplacement in its own plane of the wrench perpendicularly to the planeof the plug, the maneuvering end of the arm of the wrench may beintroduced into the groove passing through the wall of the lock casingby translating the arm parallel to the slot of the plug towards thecasing and may act on the transverse branch of the bolt in order todisplace it to its position of release from the keeper by rotating thehandle of the wrench in the corresponding direction around the bar ofthis wrench.

The plug comprises, extending perpendicularly under the latter, at leastone wall parallel to the slot in extension of the latter and allowingthe end of the arm of the wrench to be guided towards the through-grooveof the wall of the lock casing.

The plug may include two walls for guiding the arm of the wrench and oneof them includes at its end facing the lock casing, a plate divergingfrom the other guiding wall and allowing limited rotation of the arm ofthe wrench in the direction for releasing the bolt from the keeper, oncethe maneuvering end of the arm is introduced into the through-groove ofthe wall of the casing.

Preferably, the free maneuvering end of the arm of the wrench is bent soas to extend parallel to the arm towards the handle and in the directionopposite to the bar connecting the arm to the handle.

Advantageously, a shim is integral with the plug and with at least onewall for guiding the wrench on the side of the lock casing and conformedso as to fit into the substantially U-shaped portion defined by the armof the wrench between the bar and the bent end of this arm, when themaneuvering end of the arm is introduced into the through-groove of thewall of the casing.

The bolt comprises two flexible tabs located in the same plane as thetransverse branch of the bolt opposite the latter diverging from eachother in the direction opposite to the transverse branch and allowingthe bolt to be held in the lock casing after latching, when mounting thebolt in this casing, of the tabs respectively in two windows formed inboth side walls of the casing opposite to its bottom wall and twogrooves for guiding the transverse branch of the bolt, the free ends ofthe flexible tabs being supported, in the locking position of the plugand under the action of the return force of the spring, on both edges ofthe windows opposite to the guiding grooves.

The transverse branch of the bolt is part of a T-shaped end of the bolt.

Preferably, the bolt is made in a plastic material, such as polyacetal,and the return spring is in the same material as the bolt.

The bolt and its return spring are mounted in the casing by insertingthem through a conjugate imprint of the front wall of the casing and bylongitudinally pushing the bolt into the casing against the return forceof the spring until the flexible tabs elastically latch in theirrespective windows.

Alternatively, the bolt and its return spring are mounted in the casingby inserting them longitudinally through the end aperture of the casingopposite to the bottom wall of the casing.

The lock casing and the walls for guiding the arm of the wrench are casttogether with the plug.

BRIEF DESCRIPTION OF DRAWING FIGURES

The invention will be better understood and other objects, features,details and advantages thereof will become more clearly apparent in theexplanatory description which follows, made with reference to theappended drawings only given as an example illustrating an embodiment ofthe invention and wherein:

FIG. 1 is a perspective view of a plug mounted jointed on a frame in thehalf-open position and provided with a locking and unlocking deviceaccording to the invention;

FIG. 2 is a partial perspective top view of the assembly of FIG. 1 andshowing the keeper of the frame for locking the plug to this frame;

FIG. 3 is a top view of the plug of FIG. 1;

FIG. 4 is a bottom view of the plug of FIG. 1 and showing the lockaccording to the invention;

FIG. 5 is an enlarged view of the lock of the invention without itsbolt;

FIG. 6 is a perspective view of the bolt of the invention;

FIG. 7 is a top view of the bolt of FIG. 6;

FIGS. 8-11 are perspective views showing the mounting of the bolt in itslock casing;

FIG. 12 is a perspective view of the wrench of the invention used incombination with the lock of the invention;

FIG. 13 is a partial perspective top view of the plug showing theintroduction of the wrench of FIG. 12 through an aperture of the plug;

FIG. 14 illustrates the guiding of the maneuvering arm of the wrenchtowards the lock casing;

FIG. 15 illustrates a phase for maneuvering the wrench in order tointroduce the end of its arm into the lock casing;

FIG. 16 illustrates the maneuvering arm of the wrench, the end of whichis introduced into the lock casing;

FIG. 17 illustrates the position of the wrench corresponding to that ofFIG. 16;

FIG. 18 illustrates the wrench in its position for unlocking the bolt;

FIG. 19 illustrates the position of the external portion of the wrenchcorresponding to its unlocking position of FIG. 18; and

FIG. 20 is a perspective view illustrating a shim so that only thewrench of FIG. 12 may be used for unlocking the plug from its frame.

DETAILED DESCRIPTION

The locking and unlocking device of the invention is most particularlyintended for fitting out a plug, lid or the like 1, allowing a frame,chassis or the like 2 delimiting an aperture of a man-hole for example,to be blocked.

This locking device may be actuated by a wrench 3 which will bedescribed subsequently.

The locking device comprises a lock 4 integral with the internal face ofthe upper wall 1 a of the plug 1, the wall 1 a having an aperture 5opening out for providing the wrench 3 with access to the lock 4.

The wrench 3 comprises an arm 6, an end 7 of which allows the lock 4 tobe maneuvered when the wrench 3 is introduced into the aperture 5 of theplug 1 from a locking position in which a bolt of the lock 4 is retainedcaptive by a keeper 9 of the frame 1 to an unlocking position for whichthe bolt 8 is released from the keeper 9.

The plug 1 is illustrated as being of the rectangular type which may behoused in a frame with a conjugate shape 2, but of course it may have acircular shape.

According to the invention, the bolt 8 is removably mounted and guidedin translation in a lock 4 casing 10 cast together with the plug 1 andextending perpendicularly to the side of the plug 1 opposite to the oneincluding the hinge 11 of the plug 1 for jointing to the frame 2 so thatthe active portion 12 of the bolt 8 is supported, in the closingposition of the plug 1 on the frame 2, under the keeper 9 formed by arib integral with the internal face of the side of the frame 2 adjacentto the casing 10.

The lock casing 10 has the general shape of a rectangular parallelepipedand the bolt 8 is held in its position for locking the plug 1 to theframe 2, by a coil compression spring 13 mounted pre-stressed betweenthe bolt 8 and a bottom wall 14 of the casing 10 opposite to the activeportion 12 of the bolt 8.

The bolt 8 comprises a T-shaped end portion 15, the extreme branch 16 ofwhich extends transversely to the longitudinal direction of the bolt 8.

The latter further comprises two flexible tabs 17 located in the sameplane as the T-shaped portion 15 and which diverge from each other inthe direction opposite to the transverse branch 16 and consequently,towards the active portion 12 of the bolt 8.

Preferably, the bolt 8 and the return spring 13 are made in a singlepiece from plastic material, for example based on polyacetal. The activeportion 12, the flexible tabs 17, the T-shaped portion 15 and the returnspring 13 are symmetrical relatively to the longitudinal median plane ofthe bolt 8.

The tabs 17 may move elastically closer to each other at a positionsubstantially parallel to the longitudinal axis of the bolt 8.

The use of polyacetal as a material forming the bolt 8 is advantageousin that it has a good viscosity index and so a good lifetime in spite offriction which may occur between the bolt 8 and the pig iron of thecasing 10. This material also has the advantage that it allows thecompression spring 13 to be easily integrated into the rear of the bolt8.

The casing 10 comprises two grooves 18, only one of which is clearlyvisible, respectively formed in both side walls 19 of the casing 10,perpendicular to the upper wall 1 a of the plug 1, both grooves 18extending parallel to the longitudinal direction of the casing 10towards the bottom wall 14 of the latter. At least, one of the grooves18, the one which is closest to the aperture 5 of the plug 1, passesthrough the corresponding side wall 19 of the casing 10 and this wallincludes a slot 20 perpendicular to the plane of the plug 1 and openingout in the front wall 21 of the casing 10 on the one hand and in thethrough-groove 18 on the other hand so as to allow the end 7 of the arm6 of the wrench 3 to be introduced into the groove 18 as this will beseen subsequently.

Both grooves 18 respectively allow both ends of the transverse branch 16of the bolt 8 to be guided in the casing 10 along the longitudinaldirection of the latter against the return force of the spring 13 whenthe bolt 8 is displaced longitudinally in translation to its positionfor unlocking the plug 1 from the frame 2.

The casing 10 further comprises two rectangular windows 22 respectivelymade in both side walls 19 of this casing opposite to the wall 14 andgrooves 18 and extending parallel to the longitudinal direction of thecasing 10 substantially in the same plane as the guiding grooves 18.Both windows 22 are intended to receive by latching both flexible tabs17 upon mounting the bolt 8 in the casing 10.

The front wall 21 of the casing 10 is cut out so as to form an imprintwith a conjugate shape to the T-shaped portion 15 and to the compressionspring 13 of the bolt 8 so as to allow the latter to be mounted in thiscasing.

As this is better visible, notably in FIG. 8, the bolt 8 comprises a lug23 protruding perpendicularly from the planar leg of the T-shapedportion 15 of the bolt 8 and allowing the bolt 8 to be introducedmanually by translation into the casing 10 upon mounting this bolt. Thislug also allows the bolt to be unlocked from its keeper from the insideof the manhole.

The wrench 3 comprises a handle 24 parallel to the arm 6 and a bar 25perpendicular or tilted to the handle 24 and connecting the latter tothe arm 6. The arm 6 and its end 7, the handle 24 and the connecting bar25 are located in a same plane and formed by deforming a bar with arectangular cross-section.

The end 7 of the arm 6 is connected to the latter by a portion bent atright angles so that this end extends parallel to the arm 6 towards thehandle 24 and in the direction opposite to the bar 25. The wrench 3 thushas a general shape of approximately a G with the handle 24 of a lengthlarger than that of the arm 6 and of its end 7.

The aperture 5 of the plug 1 is formed by a long thin slot parallel tothe side of the plug 1 opposite to its joint 11 to the frame 2 and whichis located in a plane perpendicular to the longitudinal direction of thecasing 10.

The slot 5 has a length which is slightly larger than that of the arm 6and of its end 7 so that the arm 6 and its end 7 may be introducedthrough the slot 5 by displacing in its own plane the wrench 3perpendicularly to the upper wall 1 a of the plug 1.

The plug 1 comprises, extending perpendicularly from its internal face,two walls 26 positioned parallel to the slot 5 in extension of thelatter and allowing the end 7 of the arm 6 to be guided towards thethrough-groove 18 of the wall 19 of the lock casing 10.

Both guiding walls 26 are connected to each other by a transverse wall27 opposite to the casing 10 and defining an aperture located facing thegroove 18 and the slot 20. The guiding wall 26, located opposite to theedge of the plug 1 intended to face the edge of the frame 2 includingthe keeper 9, includes a wall 28 which diverges from the other guidingwall 26 and allows the end 7 of the wrench 3 to be limitedly pivoted inthe direction providing translational displacement of the bolt 8 in thecasing 10 towards its position for unlocking the plug 1, against thereturn force of the spring 13.

A shim 29 is integral with the internal face of the upper wall 1 a ofthe plug 1 between the divergent wall 28 and the guiding wall 26 and isfacing the through-groove 18 and the slot 20. The shim 29 is conformedso as to fit into the substantially U-shaped portion defined by the arm6 between the bar 25 and the bent end 7 of the wrench 3, when the end 7is introduced into the slot 20 at the groove 18. The shim 29 forms anobstacle for introducing a simple hook-shaped wrench in order to attemptto fraudulently unlock the bolt 8 from its keeper 9. In other words,only the wrench 3 of the invention may be used, by the presence of theshim 29, to act with its end 7 on the bolt 8 during the unlocking of theplug 1 from its frame 2.

According to an alternative embodiment, a single guiding wall 26 may beprovided, the one not including the divergent wall 28. In this case, theshim 29 is integral with the plug and with this single wall 26, and theend 7 of the wrench 3 will be supported at the bottom of thethrough-groove 18 at the position of the wrench corresponding to the onefor unlocking the bolt 8.

FIGS. 8-11 illustrate the mounting of the bolt 8 in the casing 10. Asshown in FIG. 8, the bolt 8 is shown facing the front wall 21 of thecasing 10 so that its active portion 12 is outside the casing 10 and itsT-shaped portion 15 as well as its compression spring 10 are facing theconjugate imprint made in the front wall 21 of the casing 10. The bolt 8is then introduced into the casing 10 through the wall 21 to theposition illustrated in FIG. 9 and the bolt 8 is then displaced intranslation, by means of the gripping lug 23, in the casing 10 asindicated by the arrows F1 in FIG. 9 so that both flexible tabs 17 areelastically moved closer to each other by the two end portions of theside wall 19 opposite to the bottom wall 14 as illustrated in FIG. 10until they reach both windows 22 in which they are elastically spacedapart from each other as illustrated in FIG. 11. In this position, thefree ends of both tabs 17 are in abutment, under the action of thereturn force exerted by the spring 13 supported on the bottom wall 14,onto the end edges of the windows 22 so as to hold the bolt 8 in itsposition for locking the plug 1 to the frame 2. Further, the bolt 8 isretained in the casing 10 not only by both tabs 17 housed in theirrespective windows 22 but also by the transverse branch 16 of the bolt8, the ends of which are housed in their respective guiding grooves 18.

Alternatively, the bolt 8 and its return spring 13 may be mounted in thecasing 10 by inserting them longitudinally through the aperture openingout from the casing 10 opposite to its bottom wall 14.

The unlocking of the plug 1 from its frame 2 is carried out as follows.

As illustrated in FIG. 13, the arm 6 and its end 7 of the wrench 3 areintroduced into the slot 5 of the plug 1 so that the arm 6 and its end 7arrive in the position illustrated in FIG. 14 in which a portion of thebar 25 of the wrench 3 is located between both guiding walls 26 and inproximity to the transverse wall 27, the end 7 being found at asubstantially higher level relatively to the shim 29. In this way, thewrench 3 may be displaced in a way guided by the walls 26 along adirection perpendicular to the longitudinal direction of the casing 10as indicated by the arrow F2 in FIG. 14 so that the arm 6 and its end 7arrive in the position illustrated in FIG. 15 in which the bar portion25 is supported on the end of the shim 29 opposite to the casing 10 andthe U-shaped portion defined by the arm 6 between the bar 25 and thebent end 7, i.e., at the vertical of the shim 29 so as to then allow, bytraction exerted on the handle 24 of the wrench 3 in the directionopposite to the upper wall 1 a of the plug 1, the end 7 to be introducedinto the slot 20 of the casing 10 as symbolized by the arrow F3 in FIG.15.

FIGS. 16 and 17 show that by pivoting the wrench 3 around the bar 25 inthe direction indicated by the arrow F4 (FIG. 17), the arm and its endpivot in the same direction as symbolized by the arrow F5 in FIG. 16 sothat the end 7 acts on the corresponding end of the transverse branch 16of the bolt 8 in order to displace the latter in a rectilinear andguided translation in the grooves 18 of the casing 10 against the returnforce of the spring 13 and up to a position in which the active portion12 of the bolt 8 is released from the keeper 9 of the frame 2. Pivotingof the arm 6 and of its end 7 for releasing the bolt 8 from the keeper 9is limited by the divergent wall 28.

Once the bolt 8 has been disengaged from its keeper 9, the plug 1 may belifted by means of the handle 27 of the wrench 3 around its axis 11 forjointing to the frame 2 up to its open position, completely releasedfrom this frame. In the unlocking position of the plug 1, the bolt 8 isbrought back to its locking position by the compressing spring 13. Thewrench 3 may be used for bringing the plug 1 back to its position forclosing the frame 2 by swinging around the joint 11 until the activeportion 12 of the bolt 8 automatically engages under the keeper 9against the return force of the spring 13, but the wrench 3 may quitesimply be removed from the plug 1 before swinging the plug 1 under itsown weight to its closed position locked to the frame 2 by the bolt 8.

Like for the casing 10, the guiding walls 26, 28 may be cast togetherwith the plug 1.

The bolt 8 may be removed from its casing 10 by bringing both tabs 17closer to each other and by taking out the bolt 8 through the conjugateimprint of the front wall 21 of the casing after having longitudinallydisplaced the bolt 8 facing this imprint. If necessary, the bolt 8 maybe removed from the casing 10 by longitudinally pulling the latter outof the casing after having brought both tabs 17 closer to each other.

The locking and unlocking device of the invention is of an extremelysimple and economical structure and is particularly suitable for lockinga plug or lid ensuring the safety of a child. Indeed, because a childhas limited strength, making the bolt in plastic material provides thisbolt with sufficient strength in order to ensure this safety. Further,the extremely simple configuration of the wrench 3 associated with theshim 29 at the exit of the slot for introducing the active portion 7 ofthis wrench, prevents the use of any other wrench in the form of asimple hook for fraudulently unlocking the plug 1 from its frame 2.

1. A device for locking and unlocking, with a wrench, a plug on a frame,the device comprising: a lock integral with the plug, wherein the plughas an aperture providing access to the lock for the wrench, and thewrench includes an arm with an end for maneuvering the lock, when thewrench is introduced into the aperture, from a locked position, in whicha bolt of the lock is retained captive by a keeper of the frame, to anunlocked position in which the bolt is released from the keeper, thelock further including a casing in which the bolt is removably mountedand guided in translation; and a coil compression spring interposedbetween the bolt and a bottom wall of the casing, holding the bolt inthe locked position, wherein the bolt has an end adjacent to the springand including a branch transverse to a longitudinal direction of thebolt, extending through two guiding grooves in respective side walls ofthe casing, parallel to the longitudinal direction of the bolt, at leastone of the guiding grooves passing through a first side wall of thecasing and into which the end of the arm of the wrench may beintroduced, and which may act on a corresponding end of the transversebranch of the bolt to displace the bolt translationally to a position ofrelease from the keeper, against a return force of the spring.
 2. Thedevice according to claim 1, wherein the first side of the casingincluding the guiding groove further comprises a slot perpendicular tothe first wall, opening into the guiding groove so the end of the arm ofthe wrench can be introduced into the guiding groove.
 3. The deviceaccording to claim 1, wherein the wrench comprises a handle parallel tothe arm with the end, and a bar connecting the handle to the arm, thehandle, the bar, and the arm with the end are located in a common planeand the aperture of the plug providing access to the lock is a slotextending in a plane perpendicular to the longitudinal direction of thebolt so that the arm and the end can be introduced by displacing, in itsown plane, the wrench, perpendicular to the plane of the plug, and theend of the arm of the wrench may be introduced into the guiding grooveof the wall of the lock casing by translating the arm parallel to theslot of the plug towards the casing and may act on the transverse branchof the bolt to displace the bolt to the position of release from thekeeper by rotating the handle of the wrench in a corresponding directionaround the bar.
 4. The device according to claim 3, wherein the plugcomprises at least one wall extending perpendicular from and under theplug, parallel to and as an extension of the slot so that the end of thearm of the wrench can be guided towards the guide groove of the wall ofthe lock casing.
 5. The device according to claim 4, wherein the plugcomprises two guiding walls for guiding the arm of the wrench a first ofthe guiding walls including, facing the lock casing, a plate divergingfrom a second of the guiding walls and providing limited rotation of thearm of the wrench in the direction for releasing the bolt from thekeeper when the end of the arm has been introduced into the guidinggroove of the wall of the casing.
 6. The device according to claim 1,wherein the end of the arm of the wrench is bent and extends parallel tothe arm towards the handle and in a direction opposite the barconnecting the arm to the handle.
 7. The device according to claim 6,including a shim integral with the plug and at least one guiding wallfor guiding the wrench on side of the lock casing and fitting into asubstantially U-shaped portion defined by the arm of the wrench betweenthe bar and the end of the arm, when the end of the arm is introducedinto the guiding groove of the wall of the casing.
 8. The deviceaccording to claim 1, wherein the bolt comprises two flexible tabslocated in a common plane with the transverse branch of the bolt,opposite the transverse branch and diverging from each other in adirection opposite the transverse branch for holding the bolt in thelock casing after latching, when mounting the bolt in the casing, thetabs being respectively located in respective windows in the side wallsof the casing opposite the bottom wall and both guiding grooves of thetransverse branch of the bolt, the free ends of the flexible tabs beingsupported, in the locking position of the plug by the return force ofthe spring, on edges of the windows, opposite the guiding grooves. 9.The device according to claim 1, wherein the branch of the bolt is partof a T-shaped end of the bolt.
 10. The device according to claim 1,wherein the bolt is a plastic material, and the return spring is thesame material as the bolt.
 11. The device according to claim 10, whereinthe bolt and the return spring are inserted in the casing through aconjugate imprint of a front wall of the casing against the return forceof the spring and are elastically in respective windows.
 12. The deviceaccording to claim 10, wherein the bolt and the return spring areinserted in the casing through an end aperture of the casing opposite abottom wall of the casing.
 13. The device according to claim 1, whereinthe lock casing and walls for guiding the arm of the wrench are integralwith the plug.